Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.1.1 (hexokinase)
 5,274 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Four isoenzymes of hexokinase were isolated by means of chromatography on DEAE-cellulose from soluble fraction of Vistar rat liver tissue. One of the isoenzymes (IV) was a glucokinase. Four fractions were also found in starch gel electrophoresis. These fractions catalyzed phosphorylation of glucose. Besides alterations in the total activity of hexokinase the changes in isoenzyme spectra were observed in carcinogenesis, caused by diethyl nitrosoamine. In the course of development of the blastomatose process in liver tissue content of isoenzymes I, II and, especially, of III was increased, and content of isoenzyme IV was decreased. In tissue of primary hepatomas, induced by diethyl nitrosoamine, the isoenzyme spectra of hexokinase did not significantly differ from the spectra of the enzyme in liver tissue at later stages of carcinogenesis.
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PMID:[Liver hexokinase isoenzymes in carcinogenesis]. 16 15

Established epithelial cell lines derived from livers of 7-day (B, B-R, B-3-4-7, J-C-1, J-C-13, J-5-2-1, E-C-4 and E-C-7) and adult (AL-2, AL-3, AL-4, AL-5 and AL-6) rats were analyzed for hexokinase (HK), pyruvate kinase (PK), glucose 6-phosphate dehydrogenase (G6PD), 6-phosphogluconate dehydrogenase (6PGD), glucose 6-phosphatase (G6Pase) and fructose 1,6-diphosphatase (FDPase). None of the cell lines showed appreciable activities of adult type liver enzymes (HK Type IVs (glucokinase), PK Type L, G6Pase and FDPase). On the contrary, the activities of fetal type liver enzymes (HK Types I and II, PK Type M2 and G6PD) increased markedly as compared with dispersed cells or tissues of adult liver. 6PGD gave minimum changes in activity, and the 6PGD/G6PD ratio decreased consistently. HK Type III was found only in J-C-13, AL-5 and AL-6, while HK Type IVf (high Km) was present in all the cell lines examined. Possible explanations for the undifferentiated patterns of carbohydrate-metabolizing enzymes in the established cell lines, which have several evidence of hepatocyte origin, are presented.
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PMID:Undifferentiated patterns of key glycolytic and gluconeogenic enzymes in epithelial cell lines derived from rat liver. 16 73

1. The ratio of the combined activities of hexokinase (EC 2.7.1.1) and glucokinase (EC 2.7.1.2) to the activity of glucose-6-phosphatase (EC 3.1.3.9) changed in favour of the glycolytic enzymes during pregnancy and at peak lactation. 2. There were no important changes in the ratio of the activity of phosphofructokinase (EC 2.7.1.11) to that of fructose diphosphatase (EC 3.1.3.11). 3. The ratio of the activity of pyruvate kinase (EC 2.7.1.40) to the combined activities of phosphoenolpyruvate carboxylase (EE 4.1.1.32) and pyruvate carboxylase (EC 6.4.1.1) changed in favour of the glycolytic enzyme during pregnancy and at peak lactation, but changed in favour of the gluconeogenic enzymes immediately after parturition. 4. These changes are considered in relation to the changes in food intake and hormonal status that occur during pregnancy and lactation.
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PMID:The effects of pregnancy and lactation on the activities in rat liver of some enzymes associated with glucose metabolism. 17 Sep 98

Hepatic carbohydrate metabolism in genetically diabetic mice (db/db) and their normal littermates has been studied. In db/db mice, body water was below normal and declined with age. The liver of db/db mice was abnormally large in relation to the metabolic mass of the body at all ages studied. In db/db mice, hepatic glycogenolysis, glycogen synthesis, glycogen synthetase, and phosphorylase were markedly increased. Gluconeogenesis from alanine or lactate in perfused livers of db/db mice was greater than normal per 100 g body water. Activities of fructose-1, 6-biophosphatase, glucose-6-phosphatase, glucokinase + hexokinase, and pyruvate kinase were elevated in livers of db/db mice. Diabetic mouse livers perfused with lactate showed a markedly reduced concentration of P-enolpyruvate and clear "forward crossover" between fructose-1, 6-P2 and fructose-6-P. In vivo glucose clearance, measured with [3-3H]glucose, in db/db mice was 170% that of normal mice. Data presented indicate that in livers of db/db mice: 1) glucose production is elevated prior to hyperglycemia, 2) glycogen turns over more rapidly, and 3) glycolytic and gluconeogenic enzymes are elevated paradoxically. These abnormalities are discussed from the viewpoint of their etiology.
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PMID:Hepatic metabolism of genetically diabetic (db/db) mice. I. Carbohydrate metabolism. 17 48

The activity of the glycolytic enzymes and of the glucose-6-phosphate dehydrogenase (G-6-PDH) were compared with the content of noradrenaline in rat myocardium and the liver after the intraperitoneal injection of high doses of noradrenaline. It was shown that 24 hours after int noradrenaline injection which caused exhaustion of endogenous catecholamine supply, the lactate content and the activities of lactic dehydrogenase were increased in the myocardium; the activity of hexokinase and G-6-PDH in rat myocardium and the liver were also increased, whereas the glucokinase activity was decreased. In these experiments alterations of the enzyme activities were shown to be similar to the alterations in the dystrophic tissues in which the catecholamine content was sharply decreased. The role of the sympathetic nervous system and its mediators in the mechanism of the enzyme regulation of the energy metabolism in the myocardium and the liver is discussed.
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PMID:[Activity of energy metabolism related enzymes in the myocardium and liver following administration of large doses of noradrenaline]. 17 88

Considerable thymidine kinase and pyrroline-5-carboxylate reductase activities were found in the plasma of rats bearing a transplanted lymphoma; neither activity was detected in plasma of hosts carrying hepatic, renal, mammary, or submaxillary gland tumors. All host livers exhibited signs of biochemical immaturity as indicated by the appropriate increases or decreases in the concentrations of the nine enzymes measured. The extent and time schedule of the changes in host liver varied with the enzyme and with the tumor that caused them. The hepatic concentrations of ornithine aminotransferase, arginase, pyrroline-5-carboxylate reductase, and glucokinase (all diminished), and of peptidyl proline hydroxylase and hexokinase (increased) were sensitive indicators of tumor growth in general. The concentration of ornithine aminotransferase decreased before the tumors became palpable. At more advanced stages, the high hepatic thymidine kinase activity distinguished the presence of hepatoma and lymphoma from those of all other equally fast-growing tumors. However, only in lymphoma-bearing rats did a fivefold elevation of hepatic thymidine kinase occur as early as 4 days after implantation. Additional observations on the lymphoma itself, on blood cells, and on the involuting thymus of normal rats indicate that the striking systemic effects of this tumor cannot be explained by a release of enzymes from the thymus or by the increased number of lymphoma cells present in blood or liver.
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PMID:The effect of lymphoma and other neoplasms on hepatic and plasma enzymes of the host rat. 18 34

The total activity of hexokinase (HK) and HK isoenzymic spectrum of the normal liver and slowly groming hepatoma 49 did not show any essential differences. However, the HK total activity and the relative and absolute contents of isoenzyme HK-3 were increased in hepatomas 61 and especially in the rapidly growing hepatoma 22-a. The glucokinase activity decreases in the hepatiomas 49 and 61 and disappears in the rapidly growing hepatoma 22-a. The glucose content in hepatoma 49 was slightly lower than in the normal liver, whereas in other hepatoma no traces of glucose could be detected. At low glucose concentration in the medium (0,1 mM), i.e. under conditions simulating those characteristic of tumors in vivo, the predominant form of HK in all hepatomas studied was found to be HK-3. In the liver of hepatoma-bearing mice some shifts in the value of total HK activity and its isoenzymic spectrum, reminding one of those found in hepatomas themselves, were observed. Unequal deviations in the total HK activity and its isoenzymic spectrum in hepatomas with different degrees of malignancy indicate that these characteristics are secondary rather than primary events depending on tumour progression.
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PMID:[Some characteristics of isoenzymic spectrum of hexokinase and glucose levels in hepatomas and liver of the host]. 19 29

A surgical specimen of solitary, encapsulated tumor tissue obtained from a 52-year-old male, diagnosed histologically as well-differentiated hepatocellular carcinoma (Grade II, Edmondson and Steiner) with liver cirrhosis, Type A' (and B is some parts), was found to have a supernormal level of pyruvate kinase Type L and subnormal level of Type M2; the activities (units/mg protein) being 1.21 and 0.12 respectively. The resulting isozyme pattern was apparently "superdifferentiated" as compared with those of not only the tumor-bearing, cirrhotic liver (Type L, 0.19; Type M2, 0.67) but also the normal liver (Type L, 0.47+/-0.05; Type M2, 0.18+/-0.02). The electrophoretic and kinetic properties of the type L isozyme were identical with those of the cirrhotic host liver and a non-cirrhotic control liver. Other enzyme levels in the hepatoma tissue were as follows: Glucose-6-phosphatase, norma; fructose-1,6-bisphosphatase, reduced; glucokinase, absent; and hexokinase Types I and III, and glucose-6-phosphate dehydrogenase, slightly increased. The serum alpha-fetoprotein level was 95 ng/ml. The whole enzyme profile is consistent with the minimal deviation hepatomas in rats. The results were compared with those of other human hepatomas, and the mechanisms of disordered regulation in hepatoma gene expression were discussed.
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PMID:A case of minimal deviation hepatoma in man with elevated liver-type pyruvate kinase isozyme. 19 53

The activities of hexokinase, glucokinase, phosphofructokinase, glucose-6-phosphate dehydrogenase, glucose-6-phosphatase, and fructose-1,6-diphosphatase were determined in loach embryos developed in solutions of insulin, hydrocortisone, estrone and thyroxin at different stages of embryogenesis. Glucokinase and fructose-1,6-diphosphatase activties are shown not to change markedly under the influence of the above-mentioned hormones. During some periods of early development the hexokinase activity is inhibited by insulin, estrone and thyroxin. The glucose-6-phosphate dehydrogenase activity is suppressed by each of the used hormones at all the stages of early embryogenesis while the glocose-6-phosphatase activity decreased only under the influence of insulin at the cleavage, blastula and gastrula stages. Insulin increased the activity of phosphofructokinase at the cleavage, blastula and early gastrula stages and hydrocortisone, estrone and thyroxine during certain periods of these stages. From middle gastrula two last hormones decreased the phosphofructokinase activity in the loach embryos.
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PMID:[Activity of carbohydrate metabolism enzymes in loach embryos under the influence of hormones]. 19 80

Activities of the key enzymes of glycolysis and gluconeogenesis were studied in soluble fraction of primary hepatoma, induced by diethyl nitrosamine (DENA) in rats and mice of C3HA strain. Histological structure of the tumors studied showed that they belonged mainly to highly differentiated hepatocellular adenomas. Liver tissue of the animals which were not treated with DENA, was used as a control. The hexokinase activity was increased about 2-fold in the rat hepatomas and 3-fold--in the mice hepatomas. In primary hepatomas the glucokinase activity was unaltered or slightly decreased; the fructokinase activity was distinctly decreased (in several cases down to zero). The activity of key enzymes of gluconeogenesis--glucose-6-phosphatase and fructose-1,6-diphosphatase--was distinctly decreased, especially the activity of the former enzyme, which constituted in hepatomas about 1/6 of the activity found in liver tissue.
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PMID:[Activity of enzymes of glycolysis and gluconeogenesis in primary hepatomas induced by diethylnitrosamine]. 20 3


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